Stage musicals made out of films that were already musicals to begin with, however, are more rare, and in some ways even more difficult to pull off successfully. Stage shows have a finite life (with the exception, of course, of The Mousetrap, Les Miserables and The Phantom of the Opera, which all seem to be running indefinitely), whereas films are there forever (and you can watch them for free on TV or download them cheaply). So seeing films brought to the stage – where tickets now cost up to $300 each on Brroadway and (for Elf) will cost up to a staggering £240 in the West End – requires a very special reason to see them done again.

In the case of the Open Air Theatre, Regent's Park, the venue provides its own delightful, communal reason for doing so. It's a celebratory sort of place; as Timothy Sheader, its artistic director, has commented in an interview, "I am not at all snobbish about it being an event. I love the Pimms and the prosecco and burgers. There's nothing wrong with the sense of an outing, of people leaning back happily in their seats. But sometimes, you know, you can get them leaning forward too - feeling something troubling and serious."

And underneath its light, buoyant surface, Seven Brides for Seven Brothers also has some more troubling, serious themes about forced abductions of women and then forced marriages. The show, set in 1850s Oregon and first appearing as an Oscar-winning film in 1954, perhaps belongs to a different era of sexual politics, so it will be interesting what spin director Rachel Kavanaugh – herself a veteran of this theatre, where she most recently directed a sell-out, five-star production of The Sound of Music in 2013 – puts on it.

It'll also be exciting to see two of our best younger musical theatre stars in it – Alex Gaumond, best known for his starrring roles in We Will Rock You, Legally Blonde and most recently Dirty Rotten Scoundrels in the West End, plays Adam, and Laura Pitt-Pulford, whose credits have stretched from the National Theatre to Leicester's Curve (where she has appeared in The Sound of Music, Hello Dolly! and Piaf).

The Open Air Theatre is currently riding high – its stage version of To Kill A Mockingbird, premiered two years ago, is back in London but indoors at the Barbican Theatre (following a regional tour) till July 25, while its recent productions of Peter Pan and The Seagull were both illuminating rediscoveries of familiar texts. Could this be another? Londontheatre.co.uk will be there to review it on opening night...

Seven Brides for Seven Brothers opens at the Open Air Theatre, Regent's Park, on 23 July 2015, following previews from 16 July. The show is running for a limited season until 29 August 2015.